Hypothesis: Among Qinghai's expanding deserts atop the Yellow River watershed, combining pasture management and terracing of remaining loess cliffs is an appropriate method of erosion control to still the expanding desert.
Questions: Light-colored sand, relatively free of integrated organic content, is very distinct from the dark fertile soil that neighbours it. If the sand is the new-comer, then how has it been separated from organic content? a) Washed from the soil by precipitation? b) Small organic grains carried away by the wind? c) The layer of fertile topsoil was supported by infertile sand, and constant trauma from large hooved animals beat through the top layer into the bottom?